1. Field of the Invention (Technical Field)
The present invention relates to an apparatus for accurately filling motorcycle front forks with fork oil, and a method for its use.
2. Background Art
Motorcycles, particularly used in the off-road riding sports of motocross, enduro, observed trials, hillclimbing, trail and desert riding, are typically small-displacement machines subjected to tremendous shock and torque. These "dirt-bikes" negotiate terrain virtually impassable to other vehicles. Consequently, proper operation of their suspension systems is critical to good performance and control sensitivity; the problems of suspension friction and stiction mandate proper maintenance of dirt bike suspension systems. Among essential maintenance requirements of dirt bike suspension systems is frequent and accurate filling of their front forks.
U.S. Pat. No. 806,095, to Barrow, entitled Bottle Filling Device, discloses a bottle filling device for filling a bottle with corrosive or noxious liquids, and a closure for such bottles. There is no disclosure in Barrow relating to accurate measurement of the filling liquid or use other than filling bottles.
Similarly, U.S. Pat. No. 1,834,453, to Gavaza, entitled Bottle Filling Device, discloses a device wherein fluid flow is initiated by normally squeezing a bulb to create suction. Again, there is no disclosure relating to accurate measurement of the filling fluid or adaptation to motorcycle use.
U.S. Pat. No. 2,539,841, to Katz, entitled Shock Absorber, discloses an aircraft shock absorber of telescopic structure. The device, while apparently presenting great flexibility and capacity, is not designed for motorcycle use. Likewise, U.S. Pat. No. 2,337,738, to Christiansen, entitled Double-Acting Shock Brake, discloses a telescoping shock absorber structure, but is devoid of disclosure relating to motorcycle usage or accurately refilling the absorber with fluid.
U.S. Pat. No. 3,455,349, to Greenwood, et al., entitled Fluid Filters and Apparatus for Bleeding Hydraulic Systems, discloses a hydraulic fluid air bleeding device comprising squeeze bottles and a brake fluid replacement reservoir. Significantly, precision measurement of replacement hydraulic fluid is disclosed.
In Dirt Bike, Vol. 21, No. 12, pp. 28-29, December 1991, the use of a medical syringe for replenishing motorcycle fork oil is disclosed. Manifestly lacking is an adequate reservoir of fork oil as well as a stable refilling platform.
Applicant has discovered that motorcycle forks can be filled more accurately by first overfilling the fork with fluid, then slowly withdrawing the excess of fluid to the exact amount required. Merely filling to the required amount tends to introduce inaccuracies and overfilling.